The influence of calcined mixture cooling method on hydration products composition of blended cement stone

Abstract

Complex additives based on combinations of calcined clays, including kaolinite with limestone, due to the synergetic effect play a major role in the creation of blended cements. Usually carbonate rocks contain clay impurities with adverse effects on the properties of the resultant cements and concretes. At the same time calcium carbonate contained in marl clays during calcination allows getting high-quality pozzolanic material. The effective complex additive based on the calcined mixture of clay and limestone was created. The aim of the study is to determine the effect of fast and slow cooling methods of the artificial mixture after calcination on the hydration products composition of blended cement stone with complex additives of calcined mixtures of clays and carbonates. Obtained results allow determining the conditions for obtaining effective complex additives based on calcined mixtures of ubiquitous clays and carbonate rocks for their application in blended Portland cement, and thus to expand the range of the latter. It is found that the preferred method is the fast cooling of the resulting mixture, which contributes to obtaining a complex additive with higher pozzolanic properties, compared with the additive obtained by the slow cooling method.

Keywords

• blended cement
• active mineral additives
• calcined mixture
• limestone
• polymineral clay